Japanese Unexamined Patent Application Publication No. JP2011-205979 A discloses an absorbent sheet for pets, having a liquid-permeable top sheet, a liquid-impermeable back sheet and an absorber disposed between the top sheet and the back sheet.
In this prior art, the top sheet, the absorber and a second sheet disposed between the top sheet and the absorber are integrally bonded together by embossing. The embossing here refers to a technique of press-forming a predetermined concave or convex pattern in the absorbent sheet by feeding and pressing a sheet material onto a roll or a plate having concaves or convexes. The prior art absorbent sheet is integrally formed by forming a concave or convex pattern in a predetermined region by such embossing.
In the above-described absorbent sheet integrally formed by embossing, the embossed absorber (and top sheet) has a region having a relatively high basis weight compared with a non-embossed region. Excrement from pets has a high moisture content and thus widely diffuses in the surface direction of the absorbent sheet along the embossed region having a high basis weight.
The prior art aims to promote diffusion of the excrement in the surface direction of the absorbent sheet in order to avoid excrement from being locally concentrated in the absorbent sheet.
As a general habit of pets, however, pets tend to avoid excreting again on a place which has been used once. If excrement widely diffuses, pets may not excrete on the same absorbent sheet again. Therefore, this is inconvenient contrary to the object of the absorbent sheet designed to serve for several times of excretion. In this respect, an improved technique is desired to be provided for absorbing excrement in a well-balanced manner while effectively preventing not only local concentration of excrement but excessive diffusion of excrement.